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The first recording of hallucinated music

“IT’S like having my own internal iPod,” says Sylvia. While she goes about her daily life she hears music. It may sound to her as if a radio is playing, but the music is entirely in her head.

Sylvia calls the hallucinations a nuisance, but they can be turned off, enabling researchers to investigate what causes them. Their work paves the way for treatments and hints at the cause of more common hallucinations, such as those associated with schizophrenia.

Eleven years ago, Sylvia experienced sudden damage to her hearing. About a year later, she began to hear the constant repetition of two notes. Gradually, these built into musical phrases and full melodies. “They sound like a cross between a wind instrument and a bell,” she says.

Sylvia is a musician with perfect pitch so she was able to write down the tunes and record how they developed. Some sound like familiar songs. Others resemble passages from classical tunes and some are novel melodies (listen to them at bit.ly/Sylviasmusic).

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She learned that playing real music suppressed the ghost tunes. This enabled Tim Griffiths at Newcastle University, UK, and his team to study what was going on in her brain while they switched her hallucinations off and on.

They used excerpts of classical music from Bach as a “masker” to stem the hallucinations. Just after they played a masker, Sylvia’s hallucinations were at their lowest, gradually increasing until the start of the next masker.

Meanwhile, the team used magnetoencephalography on Sylvia. This records magnetic fields produced by the electrical currents that oscillate throughout the brain – brainwaves. Sylvia’s scans showed that her musical hallucinations seemed to be generated by a network of higher brain regions, including those that process melodies and sequences of tones, and areas involved in imagery and memory. In these brain regions, when the hallucinations were happening there were more fast gamma oscillations, thought to be involved in consciousness, and more slower beta oscillations, involved in active thinking (Cortex, doi.org/qtc).

So what was going on? In most people, sound waves enter the ear and are transmitted to the brain’s primary auditory cortex. This processes sounds at their most basic level – picking out patterns and pitch, for example. From here, signals representing this information get passed to several higher brain regions that process features like melody and rhythm.

Rather than pass every detail about every aspect of sound up through each region, the brain “guesses” what is coming. If the prediction is wrong, the sound is processed until it is complete and we become aware of it as music, say, or speech. With Sylvia, incorrect predictions are not adjusted and this leads to an “aberrant conversation” in the brain that builds up to cause the hallucinations.

This explains why listening to music can stop her hallucinations. “When Sylvia is concentrating on Bach, something she is familiar with, the signal entering her brain is much more reliable and that constrains the aberrant conversation going on in the two higher areas – and they reconcile themselves to what is actually happening,” says co-author Sukhbinder Kumar at Newcastle.

“They might not arise from the same brain areas, but these observations are of importance in efforts to understand hallucinations that commonly occur in psychiatric disorders such as schizophrenia,” says Matcheri Keshavan, a psychiatrist at Harvard Medical School.

Griffiths says brain stimulation might disrupt the abnormal loops. “Better hearing aids also appear to have an effect,” he says.

Sylvia looks forward to new treatments. “I never experience quiet,” she says. “Sometimes a tune will play itself 1000 times in my head and become really annoying. I have learned to live with it but I can see how one could be driven mad.”

Sometimes a tune will play itself 1000 times in my head. I can see how one could be driven mad

This article appeared in print under the headline “The iPod in my head that never stops”